in the first line of perl script, i see: #!/usr/bin/perl -wT i think if i use -wT instead of -wt, it may cause the script to stop at a specified line which taint mode is checked. while if i use -wt just a warning is generated and execution of the perl script is not stopped. am i right?

As I wrote on your cross post on the dev shed forum, yes, that is more or less the basic idea.

From the Perlrun manpage documentation:

Quote

-t

Like -T, but taint checks will issue warnings rather than fatal errors. These warnings can now be controlled normally with 'no warnings qw(taint)'.

Note: This is not a substitute for -T ! This is meant to be used only as a temporary development aid while securing legacy code: for real production code and for new secure code written from scratch, always use the real -T.

See http://perldoc.perl.org/perlrun.html for more details.

BTW, the -w option should no longer be used for new code, use the 'use warnings' pragma instead.